Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Method and apparatus for packaging respiring produce
TECHNICAL FIELD
The present disclosure relates to packaging of
respiring produce, in particular flowers, vegetables, fruits
and/or herbs, more in particular vegetables, fruits and/or herbs
that are minimally processed.
BACKGROUND
Natural produce such as flowers, vegetables, fruits
and/or herbs tend to respire after being harvested. The
respiration continues for prolonged periods, in particular if
the produce has undergone litLle to no processing, e.g. having
been washed and possibly peeled and/or chopped up, but otherwise
fresh and uncooked. When such produce is packaged, the
atmosphere wiLhin the package is affected by the respiring
produce. Conversely, an atmosphere surrounding produce affects
the respiration, maturation, aging and/or deterioration of the
packed produce.
It has therefore become customary to package fresh
produce in packages with a modified atmosphere (Modified
Atmosphere Package or MAP) or with a controlled atmosphere
(Controlled Atmosphere Package or CAP). In MAP the produce is
packaged and an artificial gas mixture is used to establish a
distinct interior atmosphere in the package, which may however
change later on due to the respiration of the packed produce. In
CAP the produce is packaged and the composition of the package
atmosphere is controlled by including an active absorber for an
atmosphere component, e.g. an oxygen scavenger or by adapting
transmission of the packaging material to allow exchange with an
exterior atmosphere outside the package. Modified and controlled
atmosphere packaging (MAP/CAP) preserve produce quality by
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reducing the aerobic respiration rate but avoiding anaerobic
processes that may lead to adverse changes, e.g. in one or more
of colour, texture, flavour and aroma.
E.g., as explained in US 7,083,837, the quality and
shelf life of many food products is enhanced by enclosing them
in packaging that modifies or controls the atmosphere
surrounding the product. Increased quality and longer shelf life
result in fresher products for the consumer, less waste from
spoiled produce, better inventory control, and appreciable
overall savings for the food industry at both the retail and
wholesale levels. US 7,083,837 discusses that in MAP, sometimes
the package is gas-flushed with N2 or a combination of CO2 and
N2, or a combination of 0, CO2, and N2 before sealing the package
to rapidly establish the desired gas composition inside the
package. US 7,083,837 further discusses that in CAP the package
may (micro-)perforated.
Providing packages and packaging material with
perforations is also disclosed in, e.g., EP 0 351 115, WO
93/22207, US 6,441,340, US 6,730,874, WO 02/12068, US
2003/029850, WO 2006/063609, FR 2,873,992, WO 2009/132663 and EP
1 935 787, and in scientific literature such as L. Jacxsens et
al, "Validation of a systematic approach to design equilibrium
modified atmosphere packages for fresh-cut. produce", Lebensm.
Wiss. u. Technol. 32:425-432 (1999), C. Sanz et al, "Quality of
strawberries packed with perforated polypropylene" J. Food Sci.
64:748-752 (1999) and J.G. Kim et al, "Effect of initial oxygen
concentration and film oxygen transmission rate on the quality
of fresh-cut romaine lettuce", J. Sci. Food. Agric. 85:1622-1630
(2005).
WO 2014/129904 discloses that a combination of MAP and
CAP may be used.
In common MAP packaging apparatus and methods, the
modified atmosphere is established by flushing the produce
filled package and/or the location where the package is to be
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closed with one or more pure gases thus establishing an
operative atmosphere comprising a surplus amount of the pure
gas; the actual modified atmosphere within the package is then
the result of a mixture of the flushing gas and the ambient
atmosphere. These methods result in inaccurate composition of
the modified atmosphere. Further, this slows down the packaging
process significantly, e.g. by 50% when compared to a process
without gassing, and thus raises the costs of the packages
obtained. Moreover, the packaging costs are raised by the gases
and by losing these gases to the ambient atmosphere.
Improved Modified Atmosphere Packages and methods of
producing them more cost-efficient are therefore desired.
SUMMARY
In view of the preceding, herewith a method and
apparatus according to the present disclosure, and in particular
according to the appended claims, are provided.
In an aspect, therefore, a method of manufacturing a
modified atmosphere package is provided which comprises the
steps of: providing a portion of packaging material;
providing a portion of produce;
forming, from the portion of packaging material and the
portion of produce, a closed package defining a package volume
and containing in the package volume the portion of produce and
a modified atmosphere;
wherein the modified atmosphere is modified with
respect to the ambient atmosphere;
wherein the method comprises providing the modified
atmosphere in the package volume by providing a gas mixture of
at least one atmosphere modification gas and pressurised air in
the package volume.
According to the presently provided principles, the
atmosphere modification gas is mixed with pressurised air, which
is relatively cheap compared to pure gases or pure gas mixtures.
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This facilitates a thorough mixing of the air and the
modification gas to produce the gas mixture to a desired
composition in an effective and cost-efficient manner, compared
to mixing one or more modification gases with ambient air in or
near the package, as customary. Composition of the gas mixture
may therefore be better controllable. Further, this enables
flushing the package volume and replacing an initial atmosphere
therein more forcefully with reduced loss of atmosphere
modification gas compared to the known techniques. Also and/or
alternatively, the gas mixture may be provided with less
turbulence otherwise needed for mixing ambient atmosphere with
the atmosphere modification gas, which reduces or prevents
stirring up the produce in the package and/or when filling the
package with the produce. Thus, the packaging process may be
accelerated.
The packaging material may be film, e.g. a polymer
film, which may be a laminate film. Suitable polymer films are
generally known and include films made of polyethylene,
polypropylene, polyester, polyamide, and cellophane, in
monolayers and laminates. The package may be formed as a
flexible bag or pouch and/or at least part of it may be formed
as a formed tray or box which may be sealed with a formed lid
and/or a sealing film. A flexible bag or pouch may deform
significantly under the shape and/or weight of the produce and
may be suitable for robust produce and/or produce packaged in
small elements, e.g. a bag of Brussels sprouts or cut lettuce,
whereas a tray or a box may be substantially shape-retaining for
protecting large and/or delicate produce like mushrooms or
fruits such as apricots, berries etc.
The at least one atmosphere modification gas may
comprise nitrogen, argon, carbon dioxide, oxygen, ethylene, etc.
The modified atmosphere may typically have a reduced
oxygen concentration compared to the ambient atmosphere, e.g.
between 6% and 10% oxygen, or even lower to, e.g., an 02
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concentration < 4%, e.g. < 2% such as 0,5-1%, instead of about
21% in ambient air (volume percentages). Also or alternatively
it may have an elevated concentration of carbon dioxide, e.g.
between 6% and 10% carbon dioxide, or even up to 20% instead of
5 about 0,04% in ambient air (volume percentages). The gas mixture
may be composed of pressurised air and the at least one
atmosphere modification gas to certain fractions to obtain a
desired gas mixture composition. The desired composition of the
gas mixture may differ from a desired composition of the
modified atmosphere, e.g. to account for remaining ambient air
and/or (contributions of) ambient air entrapped in with the
portion of produce when closing the package, etc.
The method may comprise providing the pressurised air
by compressing air taken from the ambient atmosphere at or near
a location where the method is performed, e.g. taking in and
compressing air "on line" with manufacturing the modified
atmosphere package, possibly also comprising filling a buffer
volume. This facilitates a cost reduction and obviates providing
an external supply, e.g. a bottle bought from an external
supplier. Air taken from the ambient atmosphere may be at least
one of filtered, cleaned, dried, heated, cooled and otherwise
conditioned at least one of prior to, during and after
compression, and prior to mixing with the atmosphere
modification gas.
The step of modifying the atmosphere may comprise
mixing at least one atmosphere modification gas, possibly
several atmosphere modification gases, and the pressurised air
to a gas mixture, and introducing at least a portion of the gas
mixture into the package volume at elevated pressure. The mixing
may be done in a mixing chamber and/or a manifold from which the
mixed gas mixture is supplied, e.g. flown, to an actual location
of providing the gas mixture in the package volume. The gas
mixture may be supplied at a desired flow rate (e.g. determined
in liters per minute or per hour) and/or at a desired pressure,
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e.g. the pressure of the pressurised air, the pressure of one or
more of the atmosphere modification gases, or a summation of two
or more of these pressures, but a modified pressure, e.g.
further elevated pressure or in particular a reduced pressure
may be preferred.
In an embodiment, the method comprises measuring at
least one of the composition, an amount and a flow rate of at
least one of air to he pressurised into the pressurised air, the
pressurised air, the atmosphere modification gas and the gas
mixture, prior to introducing the gas mixture into the packaging
space.
In an embodiment, the step of forming the package
containing the portion of produce and the atmosphere is
performed in a packaging space, in particular a substantially
enclosed space such as a hag filling tube and/or a tray sealing
space, and the method comprises introducing the gas mixture in
the packaging space, and wherein the packaging space comprises a
gas inlet and a gas outlet and wherein the method comprises
measuring at least one of a composition, an amount and a flow
rate of gas at or near the gas outlet.
These latter embodiments, which may also be used in
methods of manufacturing a modified atmosphere package not
relying on pressurised air but on other gas mixtures, enable
quality control of the gas mixture and possibly adjustment of
the composition of the gas mixture. In the former embodiment,
features of the gas mixture entering the packaging space may be
monitored. In the latter embodiment establishment and/or
maintenance of a desired packaging space atmosphere composition
may be monitored and loss of gas mixture from the packaging
space may be prevented by timely reducing supplying one or more
components of the gas mixture to the packaging space. Note that
the gas outlet may be a produce inlet, in particular in a
vertical packager with a produce chute, see below. The
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measurement and/or the optional adjustment may be done by an
operator and/or automated by a controller.
The method may comprise providing the packaging
material with one or more microperforations, for establishing a
desired gas and/or humidity transmission rate through the
packaging material different from respective transmission rates
of the packaging material proper. Thus, the package may be
formed as a Controlled Atmosphere Package in which a target
package atmosphere, in particular an equilibrium atmosphere, is
established and/or maintained by interaction, preferably a
balance, between respiration of the produce on the one hand and
gas exchange between the package atmosphere and the atmosphere
surrounding the package on the other hand. The target package
atmosphere, and thus the number and/or size of the
microperforations, therefore will usually vary for different
types of produce (flowers, vegetables, leafy vegetables, fruits
and herbs, spices; washed, peeled, cut, otherwise processed or
not processed) and may vary between different batches of the
same type. One or more respiration properties of the produce may
be determined of at least a portion of (a batch of) the produce
to determine the target package atmosphere, e.g. which oxygen
concentration, carbon dioxide concentration and/or ethylene
concentration the target package atmosphere should have.
With such in mind, the method may comprise determining
a respiration property of the produce to be packaged and
determining on the basis of the determined respiration property
of the produce to be packaged a composition of the modifying
atmosphere, and -if applicable- a number of microperforations to
be made and/or a size of the one or more microperforations to be
made.
Providing the packaging material with one or more
microperforations may be done with one or more mechanical
perforators, e.g. needles which may optionally be heated, and/or
electromagnetic perforators e.g. lasers. The latter have proven
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to be reliable tools for making microperforations suitable for
packaging produce, with typical sizes in a range of 50 to 500
micrometer diameter, in particular in ranges of 70-120
micrometers, but ranges of 150-250 and/or of 250-350 micrometers
may also be suitable. The number of microperforations may
generally vary from 1 to 10 or 15 per package, some produce may
require several tens or up to a few hundreds of
microperforations. Monitoring-, in particular imaging
(photographing and/or filming) microperforations, in particular
on-line, allows for quality control, adjustment and/or other
feedback, e.g. by measuring an open area of some or, preferably,
each microperforation.
An embodiment comprises modifying the atmosphere in the
package to substantially the target package atmosphere. Thus,
the produce may be brought at least close to its equilibrium
state for prolonged quality and shelf life immediately on
packaging. However, it may be preferred to modify intentionally
the atmosphere of the package to a composition differing from
the target package atmosphere, e.g. in view of particular
storage and/or transportation criteria and/or circumstance
benefiting a different package atmosphere.
The method may comprise manufacturing a series of
modified atmosphere packages as presently provided, wherein for
each package of the series the step of forming the package
containing the portion of produce and the atmosphere is
performed in a packaging space, wherein the method comprises
providing the packaging space with the gas mixture, e.g. flowing
the space, before and/or after forming successive packages,
possibly in dependency to a rate of manufacturing successive
packages. Thus, the series of modified atmosphere packages may
be manufactured without having to repeatedly start and stop the
gas mixture, or rather to provide too much or too little of the
gas mixture for the manufacturing speed of the packages. This
facilitates and accelerates the manufacturing- process and
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improves constancy between the composition of the package
atmosphere of successive packages.
Also in view of the preceding, with benefits and
reasons applying mutatis mutandis, in an aspect an apparatus for
manufacturing a modified atmosphere package is provided. The
apparatus comprises: a device for forming, from a portion of
packaging material and a portion of produce, a closable package
when closed defining a package volume and containing in the
package volume the portion of produce and a modified atmosphere,
i.e. modified with respect to the ambient atmosphere; a supply
of pressurised air and a supply of at least one atmosphere
modification gas; and a device for providing a gas mixture of
the at least one atmosphere modification gas and the pressurised
air in the package volume.
The apparatus enables manufacturing a modified
atmosphere package effectively and cost-efficiently.
The device for providing the gas mixture may comprise a
manifold from which a gas supply conduit may run to supply the
gas mixture to an actual location of providing the gas mixture
in the package volume, e.g. by flow due to a pressure of the air
and/or the at least one atmosphere modification gas.
Although the packages may be closed by other means,
e.g. by hand, the apparatus is preferably configured to close,
e.g. seal, the package, to expedite the manufacturing process
and possibly to increase hygiene.
The apparatus may comprise a supply of packaging
material, e.g. a reel of packaging film and/or a supply of
produce, e.g. filled hopper. The apparatus may comprise a
transporter for empty packages and/or for filled packages. The
apparatus may comprise a transporter for produce at least one of
into the packaging material, onto the packaging material, and
into a package.
In an embodiment the apparatus comprises a gas inlet
for supplying the gas mixture in or near the package, and at
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least one gas sensor positioned upstream of the inlet, wherein
the gas sensor is configured to detect at least one component of
the gas mixture, in particular the at least one atmosphere
modification gas. In this text "upstream" and "downstream" refer
5 to the direction of gas flow, i.e. from the supply of
pressurised air and/or the supply of at least one atmosphere
modification gas toward the package and/or a gas outlet.
In an embodiment, the apparatus comprises a gas inlet
for supplying the gas mixture in or near the package, wherein
10 the apparatus comprises at least one of a gas outlet and a
produce inlet for supplying the produce to the apparatus and/or
to the package, positioned downstream of the gas inlet, and
wherein the apparatus comprises at least one gas sensor
positioned downstream of the inlet and upstream of, or at or
near, the gas outlet and/or the produce inlet, wherein the at
least one gas sensor is configured to detect at least one
component of the gas mixture, in particular the at least one
atmosphere modification gas.
These embodiments enable measuring the gas composition,
e.g. for quality and/or feedback purposes. The latter embodiment
may also reduce loss of valuable gas from the apparatus; note
that a produce inlet may also form a gas outlet. In some
embodiments a produce inlet may be provided with selectively
closable passages as a lock for maintaining a packaging
apparatus atmosphere within the packaging apparatus, modified
with respect to the ambient atmosphere, and for reducing
(atmosphere modification) gas loss through the produce inlet.
In a particular embodiment, the apparatus comprises an
enclosed produce supply channel, e.g. a pipe such as a chute,
having a produce filling end and a packaging end, wherein the
apparatus is configured for filling the package at or near the
packaging end with produce supplied through the channel, e.g. by
gravity, wherein the apparatus comprises a gas inlet into the
produce supply channel for supplying the gas mixture at or near
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the packaging end into the produce supply channel, and wherein
the apparatus comprises at least one gas sensor upstream of the
gas inlet and/or at least one gas sensor at or near the filling
end, and wherein the gas sensor is / the gas sensors are
configured to detect at least one component of the gas mixture,
in particular the at least one atmosphere modification gas. Such
embodiment is particularly efficient for filing bags with
produce, e.g. loose leaf salads and/or cut salads. Using the
sensors the package atmosphere may be reliably established and
gas loss from the produce filling end may be reduced or
prevented. The apparatus may be configured to produce packages
at or near the packaging end substantially simultaneously, e.g.
forming successive bags from a continuous web of film for
filling each bag from the channel during and/or shortly after
forming the bag. Such bag forming may include first forming a
tube from the web material around the channel so that the
packaging end of the channel is substantially constantly closed
off by the packaging material and a substantially constant local
atmosphere may he established at or near the packaging end.
In an embodiment comprising at least one sensor, the
apparatus may comprise a controller operably connected with the
at least one gas sensor, preferably with plural gas sensors when
present, and wherein the controller is operably connected with
one or more regulators for controlling at least one of a
composition and a flow of the gas mixture, in response to a
signal from the at least one gas sensor, e.g. controller.
operable valves, and/or wherein the controller is operably
connected with the device for forming a package, e.g. a supply
of packaging material and/or a supply of produce.
Thus a feedback system may be provided; the composition
and/or flow of the gas mixture may be regulated together with
the device for forming a package, e.g. to accommodate for
variations in packaging speed and/or to accommodate a packaging
speed to variations in the composition and/or flow of the gas
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mixture. This facilitates improving one or more of quality
control, production continuity, gas containment (i.e. reduction
of gas loss and/or flushing out unwanted gas components), etc.
In an embodiment, the apparatus comprises an enclosed
produce supply channel, e.g. a pipe such as a chute, having a
produce filling end and a packaging end, wherein the apparatus
is configured for filling the package at or near the packaging
end with produce supplied through the channel, e.g. by gravity,
wherein the apparatus comprises a plurality of gas inlets into
the produce supply channel for supplying the gas mixture at or
near the packaging end into the produce supply channel, and/or
the supply channel comprises at least partially a double wall
providing a gas flow channel inside the double wall and
comprising a plurality of gas inlets into the produce supply
channel and/or a gas inlet having an inlet opening extending for
more than about 25% of the circumference of the channel inner
wall, preferably at least 50% of the circumference, more
preferably in a range of about 75% to substantially the entire
circumference, for supplying the gas mixture at or near the
packaging end into the produce supply channel.
This may facilitate a smooth outflow of the gas,
controlling, reducing and/or preventing turbulence at or near
the packaging end and/or the package. As a result, the produce
may be transported through the supply channel more smoothly and
easily. Also spilling and/or misplacement of produce which might
end up in a sealing location and/or in a package seal may he
prevented, which would be inacceptable and cause losses.
In a particular embodiment, the channel is formed as a
substantially coaxial double walled pipe. An at least partly
double walled channel may prevent unhygienic mountings of
separate gas ducts in the channel.
In an embodiment the apparatus comprises a perforator
for providing the packaging material with one or more
microperforations. Further, a controller for the perforator
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and/or for control of (operation of) other parts of the
apparatus may be provided, e.g. a camera. Also or alternatively,
a sensor and/or controller for determining a target package
atmosphere may be provided.
It is noted that various embodiments may also be used
beneficially without a supply of pressurised air.
BRIEF DESCRIPTION OF THE DRAWINGS
The above-described aspects will hereafter be more
explained with further details and benefits with reference to
the drawings showing a number of embodiments by way of example.
Fig. 1 schematically shows an embodiment of an
apparatus and indicates at least part of an embodiment of a
method;
Fig. 2 schematically shows a gas mixing system;
Fig. 3 schematically shows, in cross section, a package
forming device of an embodiment of an apparatus and indicates at
least part of an embodiment of a method.
DETAILED DESCRIPTION OF EMBODIMENTS
It is noted that: the drawings are schematic, not:
necessarily to scale and that details that are not required for
understanding the present invention may have been omitted. The
terms "upward", "downward", "below", "above", and the like
relate to the embodiments as oriented in the drawings, unless
otherwise specified. Further, elements that are at least
substantially identical or that perform an at least
substantially identical function are denoted by the same
numeral, where helpful individualised with alphabetic suffixes.
Fig 1. shows schematically an apparatus 1 for
manufacturing modified atmosphere packages 3. The apparatus 1
comprises a package forming device 5 for forming, from portions
of packaging material 7 and portions of produce 9, modified
atmosphere packages 3 each defining a package volume V and
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containing in the package volume V a portion of produce 9 and a
modified atmosphere. Here, the packaging material is supplied as
a web of a packaging film 11 on a roll 13 for forming bags but
other forms and types of packaging material are also possible;
e.g. two or more types of packaging material may be provided,
such as trays and sealing film (not shown). In Fig. 1 the
produce is provided as separate portions 9 by a produce
transporter 14, but other ways of providing the produce as, or
into, portions 9 may be used. Here, the apparatus 1 is
configured to form and fill the packages 3and also to close and
separate them.
The apparatus 1 comprises a supply 15 of pressurised
air, here in the form of a compressor 17 provided with filters
19, and supplies 21, 23 of different atmosphere modification
gases, e.g. CO2 and 142, here in the form of gas bottles. The
compressor is provided with a buffer tank 24.
Filtering of the pressurised air may comprise plural
filtering steps, and may comprise reducing at least one of dust,
liquids, gases from the ambient air. Suitable filters may
comprise particle filters, (activated) carbon filters, gas
scrubbers, dryers, etc.
Preferably, the atmosphere modification gas(es) is
(are) also supplied pressurised so that both the pressurised air
and the atmosphere modification gas (es) are at elevated pressure
relative to the ambient atmosphere and may be transported by
flowing under their own pressure so that one or more propellers
are not needed; however, these may be provided.
The pressurised air may have a pressure of below 5 bar,
e.g. below 2 bar such as 0.5 to 1.5 bar overpressure (1 bar -
100 kPa). The atmosphere modification gas may have a similar
pressure; if gas supplies are used with high filling pressures
of up to about 200 bar overpressure, as usual, a reduction valve
should preferably be used.
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The apparatus 1 comprises a device 25 for providing a
gas mixture of one or more of the atmosphere modification gasa
from the supplies 21, 23 and the pressurised air from the supply
15 in the package volume V of each package 3 as that is formed.
5 Here, the device 25 comprises a manifold 27 connected by a gas
supply conduit 31 to the package forming device 5. The manifold
27 and an optional feedback sensor signal line 33 are connected
to a controller 29.
Also referring to Fig. 2, a suitable manifold 27 may
10 comprise for one or each of the (supplies 21, 23 of) atmosphere
modification gases and/or for the (supply 15 of) pressurised
air, a regulator 271, e.g. a pressure regulator and/or a flow
controller, possibly combined with a filter 272, a controller-
operable valve 273 and/or a hand-operable valve 274. The
15 manifold serves for combining the atmosphere modification gases
and the pressurised air as a gas mixture into the gas supply
conduit 31, which may also be provided with a controller-
operable and/or a hand-operable valve 275. Further, a gas
composition sensor 276 may be provided. Additionally, one or
more buffer tanks 277, 278 for pressurised air and/or the gas
mixture may be provided, also with Controller and/or hand
operable valves 279.
As indicated in Fig. 1, the apparatus 1 further
comprises a perforator, here a (possibly pulsed) laser 35
providing a (pulsed) laser beam 36, and a camera 37 for imaging
microperforations and/or other control processes. The laser 35
and the camera 37 are operably connected with a perforation
controller 39 for operational control, quality control and/or
feedback control of the laser 35. The controller 39 may be
programmable for determining one or more of the number, size and
positions of the microperforations.
Further, not shown in any detail, the apparatus 1 may
comprise a detector 41 and a calculator 43 configured to
determine, e.g. by measuring and calculating on the basis of
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measurement results, one or more respiration properties, e.g. an
02 consumption and/or 002-production of the produce to be
packaged and, based on that/those, determining one or more of a
composition of the target modified atmosphere, a composition of
the modifying atmosphere, a number and/or size of one or more
microperforations (to be) made in the packaging material of the
package(s).
Two or more of the gas mixture controller 29, the
perforation controller 39, the detector 41 and the calculator 43
may be interconnected (e.g. see dashed lines) and/or integrated
in one combined controller.
Fig. 3 schematically shows, in cross section, a package
forming device 5A for an apparatus in accordance with the
principles set out herein, e.g. as indicated in Fig. 1. The
device 5A comprises an enclosed produce supply channel 501,
extending in an axial direction A, here a pipe in the form of a
vertical chute for the produce from a hopper 502. The channel
501 has a produce filling end 503 and a packaging end 505.
Optionally, the hopper 502 is closable, e.g. by one or more
covers 506, to function as a lock for reduction of gas loss. The
channel 501 and the hopper 506 or other produce supply may be
integrated or separate and any spaces in between may be closed
against gas leaks or rather have one or more gas outlets. The
package forming device 5A is configured to fill packages 3 at or
near the packaging end 505 with a portion of produce 9 supplied
through the chute. The package 3 may also be formed around the
channel 501 from a (microperforated) sheet of the packaging
material, e.g. by welds or seals such as seal 4.
The shown channel 501 is double walled, having an outer
wall 507 and an inner wall 509 providing a gas flow channel 511
in between and around the circumference channel, connected to a
gas supply conduit 531 for supplying a gas mixture, in
particular a gas mixture comprising an atmosphere modification
gas and pressurised air, to the channel (Fig. 3, thin arrows).
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In fig. 3, the inner wall 309 of the channel ends within the
outer wall 507, above the bottom end of the latter (by an offset
H). Thus, the channel 501 has a gas inlet 513 into the package 3
to be filled and the channel 501 extending substantially around
the circumference of the channel inner wall 309 for supplying
the gas mixture at or near the packaging end 505 into the
produce supply channel and/or the package 3 (Fig. 3, thin
arrows). The offset H facilitates definition of the end of the
channel 501 and directing the gas into the channel 501. The
bottom end of the outer wall 509 may be provided with an inward
protrusion 509A for directing a gas flow.
The channel 501 is provided with a first gas sensor 515
upstream of the gas inlet 513, a second gas sensor 517 near the
packaging end 505 close to the gas inlet 513, and a third gas
sensor 519 near the filling end 503 both sensors 517 and 519 are
arranged on an inside of the channel 501 and downstream of the
gas inlet 513. Each of the gas sensors 515, 517, 519 is
connected to a gas composition detector and controller, possibly
integrated (cf. controller 25 of Fig. 1).
In use for manufacturing a modified atmosphere package,
an unfilled package 3 is provided at the packaging end 505 of
the channel 501, here surrounding it, and a gas mixture is
supplied to the channel 501 and the package 3 through the gas
inlet 513 (Fig. 3, thin arrows). Thus, the atmosphere at and
near the packaging end 505 and in the package 3 is modified
relative to the initial, un-modified ambient atmosphere.
Establishment of a sufficiently modified atmosphere can be
determined by detection of predetermined (not necessarily
identical) gas compositions with the second and third sensors
517 and 519. Then a portion of produce 9 is provided into the
channel 501 from the filling end 503 and filled into the package
3 (Fig. 3, bold arrow and shape 9). The portion 9 may be
supplied in one instant or in a series of partial portions.
Thereafter the filled package 3 may be closed. Thus a closed
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modified atmosphere package 3 is formed defining a package
volume V and containing in the package volume V the portion of
produce 9 and modified atmosphere containing a gas mixture of at
least one atmosphere modification gas and pressurised air in the
package volume V.
The method can thereafter be repeated with a subsequent
package and portion of produce 9. If filling of the subsequent
package is slowed for some reason, gas introduction may be
reduced and after some time stopped or restarted at or before
restarting of the filling process, based on detection data from
the sensors 515, 517, 519.
The disclosure is not restricted to the above described
embodiments which can be varied in a number of ways within the
scope of the claims. For instance, the package may be provided
with an overpressure relative to the ambient atmosphere.
Packages may be supported on a transporter during filling.
Packages may be closed by hand. Gas composition sensors may be
placed differently and/or be formed as an optical detector.
Weighing devices may be added. A (micro)perforator may be
absent. The apparatus and/or method may be provided as /
performed on new apparatus but are also possible as a retrofit.
A chute-based packaging machine need not be double walled but
may have one or more gas and/or air filling ducts. The sensor
515 or a further gas sensor may be located in a buffer tank 278.
A packaging space of a tray sealing device may be
defined by openable and closable covers.
Elements and aspects discussed for or in relation with
a particular embodiment may be suitably combined with elements
and aspects of other embodiments, unless explicitly stated
otherwise.
